How to permanently destroy saved OVRSpatialAnchors without the UUID?

I'm learning to program Spatial Anchors in Unity. I have created and saved (to local AND cloud) several OVRSpatialAnchors for testing. I didn't save the UUIDs for these. The documentation says that having leftover unused anchors stored can affect performance, but I can't find a way to list all stored anchors without providing the UUIDs, which means I can't delete them from storage. Any ideas?